Relay



1956 A. F. HORLACHER RELAY Filed Jan. 8, 1951 w m v m M 7. WM! 4 V. B

w z x m United States Patent.

RELAY Albert; E. Horlacher, Palatine, Ill., assignor to C. P Clare and Company, Chicago, 111., a corporation of Illinois Pplication January 8, 1951, Serial No. 205,023'

14 Claims. (Cl. 200-87) The present invention relates to electrical relays and more particularly to an improved direct current relay which is suitable for use in applications'where the relay structure may be subjected to considerable vibration. from external forces and yet high relay sensitivity to small currents is required.

In relay applications of the character mentioned, of

such applications do not have the required sensitivity to small currents, are usually quite complicated structurally, and are so constructed as to require a large amountsof mounting space.

Accordingly, it is an object of the present invention to provide a sensitive shockproof relay which is of. simple and economical construction, is small in size and requires only a small amount of mounting space.

It is another object of theinvention to provide an improved relay of the character described which may. be easily and quickly assembled and adjusted andmay be readily disassembled to permit replacement: or substitu tionof field coils.

In accordance with still another object of the. invem tion, the field structure, supporting frame and terminal assembly of the relay are so arranged as to facilitate disassembly thereof to permit removal and replacement of the field coils;

It is. a further object of the invention to'provideah improved relayof the character described which embodies an exceedingly simple arrangementfor supporting the contact controlling armature and for biasing: this armature to its normal setting.

The invention, both asto its organization: and method of operation, together with other objects andadvan'ta'g'es thereof will best be understood by referencetothe fol lowing specification taken in connection withtheaccompanying drawings, in which:

Fig. l is an explosionview illustrating'in disassembled relationship the components of a relay characterized.- by

the features of the present invention;

Fig. 2 is an end view of the present improved relay when fully assembled;

Fig. 3. is a side sectional view, taken along the section. lines 3-3 in Fig. 2, further illustrating the present ima proved relay; and

Fig. 4 is a top elevational view of the relay;

Referring now to the-drawing, thepresentximproved'; relay is there illustrated as generally comprising'a'frame: 10,1 a field structure 11, a stationary contact and termie; nal .assembly 12, a pair of'field coils. 13andt14 and a;

movable contact controlling armature 15. As best shown such as Allegheny electrical metal.

. 2,760,026 Patented Aug. 21, 1956 in Figs. 1 and 3, the field structure 11 comprises a pair of cores 16 and 17, a pair of L-shaped pole pieces 18 and 19 and a third U-shaped pole piece 20. All of these components are formed of a suitable magnetic material The frame 10 is of one piece construction and comprises an L-shaped member formed of non-magnetic material such as brass havinga long leg 21' extending longitudinally of the cores 16 and Wanda short leg 22 extending at right angles to the leg 21 and the cores 16 and 17.

In fabricating the present improved relay, the frame 10,'the cores 16" and 17 and the pole pieces 18 and 19 are assembled together and rigidly interconnected to form one complete sub'assembly. To this end, the cores 16 and 17 are provided at their left ends as viewed in Fig. l

nections between the described parts. In addition, small rivet-s, not shown but disposed above the cores 16 and 17, are also utilized fixedly to connect the pole pieces Iii-and '19withthe end leg 22 of the frame 10.

The cores 16 and 17 are adapted slidably to receive and support the formed bobbins 13a and14 a upon which the coils 1'3 and 14" are respectively wound. Preferably, the bobbins 13a and 14a are molded from a suitable thermosetting insulating material such as nylon having the required insulating and heat resisting properties, and areprovided'with' axial bores which fit rather tightly on the cores l6 and 17. At the ends thereof which are remote from thepole pieces 18 and 19, the cores 16 and 17 are provided with end portions 16a and 17a of reduced diameter which are threaded to mount assembly nuts 23 and 24' and are utilized to support the third pole piece 20 and the contact and terminal assembly 12. More specifically, the pole piece 20 is provided with openings 20aand 201) through the center leg thereof which are adapted to'receive the ends 16a and 17a of the cores 16 and 17. This pole piece also serves rigidly to interconnect theidentified ends of the cores 16 and 17 with the end of the frame leg 21. To this end, the lower leg 200 of the pole piece 20 is threaded to receive a flat headed machine screw 25'which extends through a suitable opening formed in the frame leg 21.

The details of'the stationary contact end terminal assembly 12 are best illustrated in Figs. 1, 2 and 3 of the drawing. As there shown, this assembly comprises a supporting member 26 molded from a suitable thermosetting insulating material such as Bakelite and having spacedopenings 27 and 28 therethrough for receiving the core ends 16a and 17a. As viewed from the front of the relay, the insulating member 26 is generally H-shaped, being provided with two spaced apart and downwardly extending legs 29 and 30 for supporting the coil terminals '31 and 32. Specifically, these terminals extendthrough' spaced apart openings in the identified legs and are spun over at their inner ends so that they are rigidly mounted upon the legs 29 and 30 of the supporting member-26. It will be understood that the terminal ends of the coils 13 and 14 may be soldered to the inner ends of the terminals 31 and 32 after the relay is assembled.

Along, its upper edge, the insulating member 26 is provided with two supporting legs 33 and 34 which are.

36a and 37a in the terminal elements 36 and 37 and are peened over at their inner ends. When mounted upon the legs 33 and 34 of the insulating member 26 in the described manner, the terminal elements 36 and 37 are provided with contact supporting ears 36b and 37b which project laterally outward from the legs 33 and 34 into the slot 35 between these legs and are disposed one above the other in the manner best shown in Fig. 3. These contact supporting ears of the terminal members 36 and 37 are respectively provided with threaded openings 36c and 37c for receiving the stationary contact screws 38 and 39. In order to clamp these screws in positions to which they may be adjusted, the ears 36b and 371; are also slotted at their outer ends as indicated at 36d and 37d to permit deformation of the ear parts into clamping engagement with the threads of the contact screws. As shown, the supporting member 26 is also provided with a centrally disposed bore 44 which is vertically aligned with the threaded opening 360 in the terminal ear 36b to permit the lower contact screw 38 to be threaded into this opening from the lower side of the member 26. The insulating member 26 is also utilized to support a terminal element 45 which, as more fully explained below, is electrically connected to the movable contact of the relay structure. Specifically, this terminal element is provided with spaced openings 45a and 45b for receiving the core ends 16a and 17a and is adapted to act as washer means against which the assembly nuts 23 and 24 are drawn in assembling the terminal and contact assembly 12 with the field structure 11 of the relay.

As best shown in Figs. 1 and 3 of the drawing, the pair of L-shaped pole pieces 18 and 19 are respectively provided with pole face legs 18a and 19a which extend toward the front end of the relay, i. e., toward the contact and terminal assembly 12. The third pole piece 29 is likewise provided with a pair of spaced apart pole face legs 20c and 26d which extend rearwardly of the the pivot pin 46 in the recess d and of biasing the relay toward and in alignment with the pole face legs 18a and 19a of the pole pieces 18 and 19. As will be seen in Fig. 3, the pole face legs 13a and 19a of the two pole pieces 18 and 19 are vertically displaced above the pole face legs 20c and 20d by an amount such that the lower surfaces of the legs 18a and 19a are vertically displaced above the upper surfaces of the pole face legs 20c and 20d; this for the purpose of permitting the relay armature to be mounted in overlapping relationship with the identified pole face legs while preserving a parallel relationship between the armature and the axis of the coils 13 and 14 in the manner more fully explained below.

In order selectively to move a movable contact 15f back and forth between the opposed contact ends 38a and 39a of the contact screws 38 and 39, thereby to perform the desired circuit switching operations, the armature 15 which is provided to actuate the movable contact 15;", is pivotally supported intermediate its ends at a point approximately midway between the ends of the field structure 11. More specifically, this elongated armature is provided with a rear end portion 15a which is disposed in proximity to and overlaps the under sides of the pole face legs 18a and 19a and is provided with an opposed front end portion 15b which is disposed in proximity to and overlaps the upper sides of the pole face legs 26c and 20d. In the central portionthereof, the armature 15 is provided with a rectangular opening 15c which is intersected by a transversely extending recess 150. provided to seat a pivot pin 46. Along the front edge and midway between the sides thereof, the armature 15 is also provided with a projecting contact finger 1Se which fixedly mounts the movable contact 15f at the extended end thereof.

In accordance with one important feature of the present invention, an elongated flat spring element 47 is provided which is utilized for the dual purpose of clamping armature 15 in a direction to move the opposed end portions 15a and 15b thereof away from the pole face legs of the pole pieces 18, 19 and 20. More specifically, the spring element 47 is provided with a first rectangular portion 47a which is slightly dished in the manner shown in Fig. 1 and is adapted to extend upwardly from the bottom side of the armature through the opening 15c, over the pivot pin 46 and back through the opening so that the front end thereof overlaps the under side of the armature. This portion of the spring element 47 is provided with spaced apart tool receiving openings 470 which are used in assembling the relay. The spring element 47 is also provided with a second portion 47b which extends along the under side of the armature and projects beyond the rear end of the armature. When the three components 15, 46 and 47 are assembled, the pivot pin 46 is clamped in position within the recess 15d so that the ends thereof project beyond the sides of the armature. If desired, the pivot pin 46 may be provided with a centering slot along the length and midway between the ends thereof for receiving the spring part 47a and thus prevent longitudinal movement of the pivot pin in the recess 15d.

For the purpose of pivotally supporting the pivot pin 46 at the ends thereof, the frame member 10 is provided with bendable arms 48 and 49 which project outwardly from the rear leg 22 of the frame along opposite sides of the armature and are provided at their ends with hearing holes 43a and 49a for receiving the ends of the pivot pin 46. To prevent the sides of the armature from frictionally engaging the supporting arms 43 and 49, the supporting ends of the latter are provided with pressed-in portions which form inwardly extending bosses 48b and 49b coaxially with the bearing holes 48a and 49a. These bosses are adapted to engage the armature sides adjacent the pivot pin and thus prevent the rearwardly extending side edges of the armature from scraping against the supporting arms 43 and 49.

In order to utilize the spring element 47 as an armature biasing spring, the frame 10 is equipped with an ear 50 which extends outward from the rear leg 22 of the frame and projects between the pole face legs 18a and 19a of the pole pieces 13 and 19. This car is provided with a threaded opening for receiving a threaded adjusting screw 51. Specifically, the lower end of the screw 51 passes by the rear edge of the armature 15 and engages the extended end of the second spring portion 47!; to bias the armature 15 for counterclockwise movement about its pivotal axis.

Briefly to consider the manner in which the component parts of the relay are assembled to form the described relay structure, it is again noted that the parts 10, 16, 17, 18 and 19 are separately assembled to form a complete subassembly. Also, the parts of the terminal and contact assembly 12, i. e., the parts 26, 31, 32, 36, 37, 38, 39, 40 and 41 are separately assembled to form a subassembly. In bringing the described subassemblies and other parts of the relay into fully assembled relationship, the coils 13 and 14 are first slipped onto the cores 16 and 17 respectively, following which the pole piece 20 is telescoped over the ends 16a and 17a of the coils 16 and 17 until the center leg of this pole piece abuts the shoulders terminating the reduced diameter ends 16a and 17a of the cores 16 and 17. In this connection, it is noted that the coil bobbins 13a and 14a are of substantially the same length as the main sections of the cores 16 and 17 so that when the pole piece 20 is brought to bear against the shoulders along the two cores, the coils are prevented from moving longitudinally of the cores. With the pole piece 20 in the position indicated, the assembly screw 25 may be threaded into the tapped opening in the pole piece leg 200 through the screw receiving opening in the end of the frame leg 21, thereby to complete the field structure assembly and w to hold, the coils 13 and 14 in their assembled positions on the cores Hand 17.

The next operation is that of assembling the terminal and contact assembly 12 with the field structure 11. To this end, the core ends 16a and 17a are extended through the openings 23 and 27 in the supporting member 26, following which the terminal element 45 is posltioned on the core ends 16a and 17a and the assembly nuts 23 and 24 are threaded on these core ends to clamp the member 26 between the pole piece 20 and the ter minal element 45. The final operation is that of assembling the armature 15 with the remaining components of the relay structure. This is accomplished. by positioning the spring 47 to project the portion; 47a thereof through the opening 150 in the center portion of the armature. A hairpin-like assembly tool having outturned ends inserted through the openings 470 in the, spring part 47a from the top side of the armature 15 may now be used to move the two parts 15 and 47' into their final assembly positions in the relay structure. Specifically, this tool is manipulated to move the armature 15 until the movable contact 15f-is inserted between the contact ends 38a and 39a of the contact screws 38 and 39, after which the armature 18 may be moved rearwardly to position the rear end portion 15a thereof beneath the pole face legs 155a and 19a of the pole pieces 18 and 19 and to bring the recess 15d in alignment with the bearing openings 43a and 49a in the supportingarms 48 and 4-9. With the rear end portion 15a of the armature 15 bearing against the under sides of the pole face legs 18a and 19a and the movable contact bearing against the contact end 39:; of the screw 39, the described hairpin-like assembly tool may now be pulled away from the relay field and frame structure to flex the spring portion 4'? away from the recess 15d and thus permit the pivot pin 46 to be inserted through the bearing hole-49a along the recess 15d, beneath the spring portion 47a and through the bearing hole 43a to establish the desired pivotal mounting for the armature 15. After'the pin 46 is thus moved to the desired position, the hairpin tool may be withdrawn from the opening 470 in the spring portion 47a, permitting this spring portion partially to return to its normal unilexed setting, thereby to clamp the pivot pin 46 in the recess 15d. Thus, the armature 15 is pivotally supported at the ends of the supporting arms 48 and 49. Following this operation, the biasing screw 51 may be threaded into the car 50 to engage the rear end of the spring part 4-7!) and establish the desired bias on the armature 15.

Briefly to consider the manner in which the present improved relay may be adjusted, it will be understood that the stationary contact screws 38 and 39 may be adjusted as required to establish the desired amount'of armature travel between the back and front contact positions of the movable contact 15 Further, the biasing screw 51 may be adjusted as required to establish the desired normal bias on the armature 15 to preventthe movable contact 15 from c'hatteringwhen engaged with the stationary back contact 39a while permitting positive operation of the armature to the contact make or front contact position when the coils 13 and 14 are energized. In this regard, the desirability of maintaining air gaps of the same length between the ends of the armature 15 and the pole face legs 18a, 19:1, 200 and 2th] of the three pole pieces will be readily apparent. Adjustment of the lengths of the air gapsbetween the ends of the armature and one or more of the identified pole face legs of the pole piecesmay be made by using a pair of pliers to bend the supporting arms 48 and, 49

up or down relative to the frame leg 21, thereby to change the position of one or both of the supports for the pivot pin 46.

From the preceding explanation, it willbe understood that in order to rotate the armature 15 to move the movable contact 15 out of engagement with the back contact-39a and into, engagement with the front contact 38a, it is necessary to energize the field coils 13 and 14; Since'the terminals of both coils are separately brought out to the terminal elements 29 and 30, it will also be understood that these coils may be energized in series or parallel as desired. When energized, a magnetic field is set, up in the field structure which traverses the cores 16 and 17, the pole pieces 18, 19 and 20,.the armature 15 and the air gaps between the ends of this armature and the pole face legs of the identified pole pieces. The resulting magnetic attraction between the pole face legs of the pole pieces and the opposed ends of the armature 15; causes this armature to be pivoted in a clockwise direction as viewed in Fig. 3 against the bias of the spring 47 to move the contact 15f out of engagement with the back contact 39a and into engagement with the front contact 38a. In this regard, it will be understood that the two stationary contacts 38a and 39a are insulated from the remaining parts of the relay structure.- The movable contact 15 on the other hand, is connected to thecommon terminal element 45 over a conductive path which includes the armature 15, the spring 47, the screw 51, the frame 10 and the cores 16 and 17. It will be noted that all parts of this conductivepath are either clamped or stressed into engagement so that the contact resistances between the different pairs of engaged parts are relatively low, and hence the overall resistance of, the described path is small.

From. the foregoing explanation, it will be understood that the present improved relay is of simple and economical construction and is highly compact in arrangement. Moreover, the arrangement of the magnetic circuit is such that a maximum amount of magnetic pull is exerted upon the armature 15 with a given amount of power ini put to the field coils 13 and 14. In this regard, it will benc-ted that all of the magnetic flux produced in the field structure traverses the armature 15, that large poleface areas are provided to-overlap both ends of the armature and thus assist in moving the armature to its contact make position against the bias of the spring 47, and that the structure is so arranged that very short air gaps maybe used throughout. It will alsobe apparentthat the present improved structure is so compact that it may be mounted in a very small space in either of two positions. Thus, the threaded openings 22a in the frame leg22 may be, employed to receive mounting screws for the purpose of mounting the relay in an upright position, in whichcase the mounting space required for the relay is they rectangular area defined by the outer edges of the insulating member 26. On the, other hand, the threaded openings 21a in the frame leg 21 may be employed to receive the endsof, mounting screws used to mount the relay in a horizontal position, in which case the mounting space required is approximately the area defined by the length and width of the relay as shown in Fig. 4. in either case, the longest dimension or the mounting space required is something less than two and one-half inches. As will be apparent from the above description of the armature supporting arrangement, the relay is relatively insensitive to vibratory forces impressed thereon from external sources. Specifically, the shockproof character of the relay structure is achieved by so mounting the armature 15 that this armatureis dynamically balanced. In this connection, it is noted that the portion of the armature which extends rearwardly from the pivot pin. 46 toward the pole pieces 18 and 19 is of the correct mass to counterbalance the mass of the forward end of the armature, the fingerlSe and the, movable contact 15, carried by this finger. achieve precise dynamic balancing of the armature 15, the length of the rear end portion 15a of the armature is made greater-than the length of the front end portion 15b by an amount suchthat the extra material in the rear endv armature portion 15a .counterbalances thefinger a and the movable contact 15f. With this arrangement, vibratory forces impressed upon the armature 15 through the supporting frame 10 have the effect of tending to move both end portions of the armature in the same direction and thus cancel out with the result that no appreciable movement of the armature is produced in response to such forces.

While one embodiment of the invention has been described, it will be understood that various modifications may be made therein which are within the true spirit and scope of the invention as defined in the appended claims.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

l. A relay having a movable contact, comprising a field structure provided with at least one pole piece, a movable contact controlling armature having a portion disposed in proximity to said pole piece, a supporting member, a spring engaged at two places by the armature and engaged by the supporting member intermediate said two places pivotally to support said armature on said supporting member, and means including said spring for biasing said armature in a direction to move said portion thereof away from said pole piece.

2. A relay having a movable contact, comprising a field structure provided with at least one pole piece, a movable contact controlling armature having a portion disposed in proximity to said pole piece and provided with an opening through a second portion thereof, a spring carried by said armature and provided with an intermediate portion extending through said opening, means including said intermediate portion of said spring for pivotally supporting said armature, and means coacting with said spring to bias said armature in a direction to move said first-named portion thereof away from said pole piece.

3. A relay having a movable contact, comprising a field structure including a pair of spaced apart pole pieces, a movable contact controlling armature having opposed ends disposed in proximity to said pole pieces and provided with an opening through a central portion thereof, a spring provided with a portion extending through said opening, and means including said spring for pivotally supporting said armature intermediate the ends thereof and for biasing said armature in a direction to move the ends thereof away from said pole pieces.

4. A relay having a movable contact, comprising a field structure including a pair of spaced apart pole pieces, a movable contact controlling armature having opposed ends disposed in proximity to and spaced from opposite sides of said pole pieces, said armature being provided with an opening through a central portion thereof, a spring provided with a first portion extending through said opening and a second portion extending beyond one of the ends of said armature, means including said spring ror pivotally supporting said armature intermediate the ends thereof, and means coacting with said second portion of said spring to bias said armature in a direction to move the ends thereof away from said pole pieces.

5. A relay having a movable contact, comprising a field structure including a pair of spaced apart pole pieces, a movable contact controlling armature having opposed ends disposed in proximity to said pole pieces and provided with an opening through a central portion thereof, said armature having a recess extending transversely thereof and intersecting said opening, a pivot pin disposed in said recess and provided with ends projecting beyond the sides of said armature, a spring provided with a first portion extending through said opening over said pivot pin and back throu h said opening to clamp said pivot pin in said recess, means coacting with the ends of said pivot pin pivotally to support said armature, said spring including a second portion extending beyond one end of said armature, and means coacting with said second portion of said spring to bias said armature in a direction to move the ends of said armature away from said pole pieces.

6. A relay having a movable contact, comprising a field structure including a pair of spaced apart pole pieces, a movable contact controlling armature having opposed ends disposed in proximity to said pole pieces and provided with an opening through a central portion thereof, said armature having a recess extending transversely thereof and intersecting said opening, a pivot pin disposed in said recess and provided with ends projecting beyond the sides of said armature, a spring provided with a first portion extending through said opening over said pivot pin and back through said opening to clamp said pivot pin in said recess, a frame supporting said field structure and pro vided with bendable arms extending longitudinally of said armature on either side thereof, said arms having bearing holes at the ends thereof for receiving the ends of said pivot pin, thereby pivotally to support said armature, said spring including a second portion extending beyond one end of said armature, and means adjustably carried by said frame for engaging said second portion of said spring at a point beyond said one end of said armature, thereby adjustably to bias said armature in a direction to move the ends of said armature away from said pole pieces.

7. A relay comprising a field structure including a pair of spaced apart pole pieces, an armature having opposed ends disposed in proximity to said pole pieces and provided with an opening through a central portion thereof, said armature having a recess extending transversely thereof and intersecting said opening, a pivot pin disposed in said recess and provided with ends projecting beyond the sides of said armature, a spring provided with a first portion extending through said opening over said pin and back through said opening to clamp said pin in said recess, means coacting with the ends of said pivot pin pivotally to support said armature, a contact carrying finger projecting from one end of said armature and counterbalanced by the other end of said armature, said spring including a second portion extending beyond the other end of said armature, and means coacting with said second portion of said spring to bias said armature in a direction to move the ends of said armature away from said pole pieces.

8. A relay comprising a field structure including a pair of spaced apart pole pieces, an armature having opposed ends disposed in proximity to said pole pieces and provided with an opening through a central portion thereof, said armature having a recess extending transversely thereof and intersecting said opening, a pivot pin disposed in said recess and provided with ends projecting beyond the sides of said armature, a spring provided with a first portion extending through said opening over said pin and back through said opening to clamp said pin in said recess, a frame supporting said field structure and provided with bendable arms extending longitudinally of said armature on either side thereof, said arms having bearing holes at the ends thereof for receiving the ends of said pivot pin, thereby pivotally to support said armature, a contact carrying finger projecting from one end of said armature and counterbalanced by the other end of said armature, said spring including a second portion extending beyond the other end of said armature, and means adjustably carried by said frame for engaging said second portion of said spring at a point beyond said other end of said armature, thereby adjustably to bias said armature in a direction to move the ends of said armature away from said pole piecesv 9. A relay having a movable contact, comprising a field structure including a pair of spaced apart cores, a pair of L-shaped pole pieces separately connected to said cores at the same ends thereof and a third U-shaped pole piece detachably connected to said cores at the other ends thereof, said pair of pole pieces having pole face legs extending toward said third pole piece and said third pole piece having a pole face leg extending toward the pole face legs of said pair of pole pieces, an L-shaped frame rigidly connected to said cores and said pair of pole pieces to form a sub-assembly and provided with a leg end detachably connected to one leg of said third pole piece,

coils slidably supported upon said cores, a terminal and contact assembly removably supported on said cores at the same ends thereof as said third pole piece, whereby said coils may be removed from said cores after first disconnecting said assembly and third pole piece from said core ends and frame, a movable contact controlling armature having opposed ends disposed in proximity to the pole face legs of said pole pieces, and means pivotally supporting said armature intermediate its ends upon said frame.

10. A relay having a movable contact, comprising a field structure including a pair of spaced apart cores and pole pieces connected to said cores at the ends thereof and provided with pole face ends extending toward each other, one of said pole pieces being removably supported on corresponding ends of said cores, coils slidably supported on said cores, a terminal and stationary contact assembly removably supported on the same ends of said cores as said one pole piece, whereby said coils may be removed from said cores after first removing said assembly and one pole piece from said core ends, a movable contact controlling armature having opposed ends disposed in proximity to the pole face ends of said pole pieces and provided with an opening through a central portion thereof, a spring provided with a first portion extending through said opening and a second portion extending beyond one end of said armature, means including said first portion of said spring for pivotally supporting said armature intermediate its ends, and means coacting with said second portion of said spring for biasing said armature in a direction to move the ends thereof away from the pole face ends of said pole pieces.

11. A relay having a movable contact, comprising a field structure including a pair of spaced apart cores and pole pieces connected to said cores at the ends thereof and provided with pole face ends extending toward each other, a frame supporting said field structure, one of said pole pieces being detachably connected to corresponding ends of said cores and detachably connected to said frame, coils slidably supported on said cores, a terminal and stationary contact assembly removably supported on the same ends of said cores as said one pole piece, whereby said coils may be removed from said cores after first disconnecting said assembly and one pole piece from said core ends and frame, a movable contact controlling armature having opposed ends disposed in proximity to the pole face ends of said pole pieces and provided with an opening through a central portion thereof, said armature having a recess extending transversely thereof and intersecting said opening, a pivot pin disposed in said recess and provided with ends projecting beyond the sides of said armature, a spring provided with a first portion extending through said opening over said pivot pin and back through said opening to clamp said pivot pin in said recess, said frame having bendable arms extending longitudinally of said armature on either side thereof for pivotally supporting said pivot pin at the ends thereof, thereby pivotally to support said armature, said spring having a second portion extending beyond one end of said armature, and means carried by said frame for coacting with said second portion of said spring to bias said armature in a direction to move the ends thereof away from the pole face ends of said pole pieces.

12. A relay having a movable contact, comprising a field structure including a pair of spaced apart cores, a pair of L-shaped pole pieces separately connected to said cores at the same ends thereof and a third U-shaped pole piece detachably connected to said cores at the other ends thereof, said pair of pole pieces having pole face legs extending toward said third pole piece and said third pole piece having a pole face leg extending toward the pole face legs of said pair of pole pieces, an L-shaped frame rigidly connected to said cores and said pair of pole pieces to form a subassembly and provided with a leg end detachably connected to one leg of said third pole piece, coils slidably supported upon said cores, 2. terminal and contact assembly removably supported on said cores at the same ends thereof as said third pole piece, whereby said coils may be removed from said cores after first disconnecting said assembly and third pole piece from said core ends and frame, a movable contact controlling armature having 0pposed ends disposed in proximity to the pole face legs of said pole pieces and provided with an opening through a central portion thereof, said armature having a recess extending transversely thereof and intersecting said opening, a pivot pin disposed in said recess and provided with ends projecting beyond the sides of said armature, a spring provided with a first portion extending through said opening over said pivot pin and back through said opening to clamp said pivot pin in said recess, said frame having bendable arms extending longitudinally of said armature on either side thereof for pivotally supporting said pivot pin at the ends thereof, thereby pivotally to support said armature, said spring having a second portion extending toward said pair of pole pieces and projecting beyond the end of said armature, said frame having an ear extending between the pole face legs of said pair of pole pieces and overlying said second portion of said spring, and an adjustable armature biasing screw threaded through said ear and engaging said second portion of said spring, thereby adjustably to bias said armature in a direction to move the ends of said armature away from the pole face legs of said pole pieces.

13. A relay comprising a field structure including a pair of spaced apart pole pieces, an armature having opposed ends disposed in proximity to said pole pieces, a supporting member, spring means engaged at two places by said armature and engaged intermediate thereof by said sup porting member to pivotally support said armature on said supporting member, means including said spring means for normally biasing the ends of said armature away from said pole pieces, and a contact carrying finger projecting from one end of said armature and counterbalanced by the other end of said armature.

14. A relay having a movable contact comprising a field structure having a pole piece, an armature supporting structure, a movable contact controlling armature having a portion thereof disposed in proximity to said pole piece and having ends, means including a spring mounted on said armature and pivotal supporting means carried by said supporting structure intermediate the ends of the armature for supporting said armature for pivotal movement about an axis intermediate the ends of said armature, and means carried by said supporting structure for engaging said spring to bias said portion of said armature away from said pole piece.

References Cited in the file of this patent UNITED STATES PATENTS 125,806 Goodyear Apr. 16, 1872 862,084 Lorimer July 30, 1907 909,594 Heinze Jan. 12, 1909 1,167,067 Hill Jan. 4, 1916 1,534,753 Watson Apr. 21, 1925 1,568,589 Eddington Jan. 5, 1926 1,606,164 Garvin Nov. 9, 1926 1,696,170 Leak-e Dec. 18, 1928 1,709,571 Harrison Apr. 16, 1.929 2,253,483 Menzel Aug. 19, 1941 2,344,809 Eaton Mar. 21, 1944 2,422,986 Ring June 24, 1947 2,455,049 Edwards et al Nov. 30, 1948 FOREIGN PATENTS 35,824 Denmark Mar. 29, 1926 448,948 Great Britain Jan. 18, 1936 588,849 Germany Feb. 6, 1931 

